如何平滑Android相机的自动对焦

Question

Definition: Jumpy - What appears to be zooming in and then zooming back out to autofocus.

I am writing an Android app that displays a Camera preview. I have noticed that on my HTC One M8, the autofocus is very jumpy.

I am using android.hardware.Camera, but have seen this on the camera2 samples as well. I have tried Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE, for example, with no success. I am getting a very smooth autofocus camera preview with OpenCV. Am I missing something? I can't be the only one seeing this.

EDIT: Code based mostly from this article: http://developer.android.com/guide/topics/media/camera.html

Answer 1

After much research, I have determined that this is an implementation issue causing what is sometimes referred to as "breathing". This happens almost every time .autoFocus(...) is called manually, or when it is called continuously.

I can only assume that OpenCV, using the native Camera.h API, must have much better control over how autofocusing is done. It still bounces, but is noticeably smoother.

I've noticed my Camera app that comes with Android also "breathes" very heavily. Because of this, I can only assume it is a systemic issue outside of my control, for the most part.